Tutorial by Examples: f

class Message DEFAULT_MESSAGE = "Hello, world" def speak(message = nil) if message puts message else puts DEFAULT_MESSAGE end end end The constant DEFAULT_MESSAGE can be changed with the following code: Message::DEFAULT_MESSAGE = "Hullo, wo...

The easiest way to install and manage various versions of Ruby with rbenv is to use the ruby-build plugin. First clone the rbenv repository to your home directory: $ git clone https://github.com/rbenv/rbenv.git ~/.rbenv Then clone the ruby-build plugin: $ git clone https://github.com/rbenv/rub...

In Emacs M-x slime will start slime with the default (first) Common Lisp implementation. If there are multiple implementations provided (via variable slime-lisp-implementations), other implementations can be accessed via M-- M-x slime, which will offer the choice of available implementations in mini...

// This iterates through a range between two DateTimes // with the given iterator (any of the Add methods) DateTime start = new DateTime(2016, 01, 01); DateTime until = new DateTime(2016, 02, 01); // NOTICE: As the add methods return a new DateTime you have // to overwrite dt in the itera...

Example: Invoke different constructors by passing relevant parameters import java.lang.reflect.*; class NewInstanceWithReflection{ public NewInstanceWithReflection(){ System.out.println("Default constructor"); } public NewInstanceWithReflection( String a){ ...

Reflection is useful when it is properly used for right purpose. By using reflection, you can access private variables and re-initialize final variables. Below is the code snippet, which is not recommended. import java.lang.reflect.*; public class ReflectionDemo{ public static void main(St...

var baseType = typeof(List<>); var genericType = baseType.MakeGenericType(typeof(String)); var instance = Activator.CreateInstance(genericType); var method = genericType.GetMethod("GetHashCode"); var result = method.Invoke(instance, new object[] { });

This iterates from 4 to 13 (inclusive). for i in 4..13 puts "this is #{i}.th number" end We can also iterate over arrays using for names = ['Siva', 'Charan', 'Naresh', 'Manish'] for name in names puts name end

If your enum class is required to have static fields, keep in mind they are created after the enum values themselves. That means, the following code will result in a NullPointerException: enum Example { ONE(1), TWO(2); static Map<String, Integer> integers = new HashMap<>(); ...

The Java language provides three operator for performing bitwise shifting on 32 and 64 bit integer values. These are all binary operators with the first operand being the value to be shifted, and the second operand saying how far to shift. The << or left shift operator shifts the value g...

import java.io.FileReader; import java.io.IOException; import javax.script.ScriptEngine; import javax.script.ScriptEngineManager; import javax.script.ScriptException; public class InterfaceImplementationExample { public static interface Pet { public void eat(); } p...

An important principle for unit testing is to separate data access from business logic. One efficient technique for this is to define interfaces for data access. Your main class always use a reference to that interface instead of direct reading or writing data. in production code the main class wil...

GWT ships with a command line utility called webAppCreator that automatically generates all the files you’ll need in order to start a GWT project. It also generates Eclipse project files and launch config files for easy debugging in GWT’s development mode. You can create a new demo application in a...

You should already have your backend REST resource available. On the client side (GWT) your need to Add RestyGwt dependency to your project with maven <dependency> <groupId>org.fusesource.restygwt</groupId> <artifactId>restygwt</artifactId> <vers...

Let's say you have this line of code: printf("Hello, world!\n"); Now say you want to change the text to "Program exiting." CommandBufferMnemonicci"printf("¦");change in the ".Program exiting.\n<esc>printf("Program exiting.\n");

Using else we can perform some task when the condition is not satisfied. But what if we want to check a second condition in case that the first one was false. We can do it this way: a = 9; if mod(a,2)==0 % MOD - modulo operation, return the remainder after division of 'a' by 2 disp('a is ev...

To check if a required gem is installed, from within your code, you can use the following (using nokogiri as an example): begin found_gem = Gem::Specification.find_by_name('nokogiri') require 'nokogiri' .... <the rest of your code> rescue Gem::LoadError end However, this can ...

This can be easily accomplished by calling Enumerable#to_a on a Range object: (1..10).to_a #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] (a..b) means that it will include all numbers between a and b. To exclude the last number, use a...b a_range = 1...5 a_range.to_a #=> [1, 2, 3, 4] or...

While in insert mode, you can use <C-r> to paste from a register, which is specified by the next keystroke. <C-r>" for example pastes from the unnamed (") register. See :help registers.

The MAF file format is a tab-delimited text file format intended for describing somatic DNA mutations detected in sequencing results, and is distinct from the Multiple Alignment Format file type, which is intended for representing aligned nucleotide sequences. Column headers and ordering may someti...